Photographic camera



May 4 1926.

J. TESSIER PHOTOGRAPHIC CAMERA Filed Fe 8. 1925 2 Sheets-Sheet 1Patented May. 4, 1926.

mm TEBSIEB,

PANY, OF ROCHESTER, NEW YOBK,

OF ROCHESTER, NEW YORK, ASSIGNOR T0 EASTMAN KODAK CO!- A conroaa'rron ornew Yonx.

PHOTOGRA PHTC CAMERA.

Application fled February 8, 1828. Serial no. 817,888. i

To all whom it may concern:

Be it known that I, JULIEN Tnssmn, a

citizen of the Republic of France, residing at Rochester, in: the countyof Monroe and State of New York, have invented certain new and usefulImprovements in Photographic Cameras, a full, clear, and exactspecification.

This invention relates to photographic cameras and more particularly tothe correlation of the finder and objective in a camera. I

It is a common fault in cameras that the fields of the finder and ofthecamera objective do not coincide, usually because their optical axes areparallel and separated and no means of compensating for this error,known as stem-parallax, is provided. If the subjects to be taken are ata. considerable distance, the error is small; but when, as in motionpicture work, the subject is frequently very near, it is so great-thatit cannot be ignored. The principal object of this invention is to'rovide a camera in which the finder and 0 jectives are so correlatedthat at all times the finder field will aiid in which this correlationtakes place automatically operator. A further object is to provide sucha mechanism which is simple and not liable to derangement, and which hasa low manufacturing cost.

These and other objects will appear from sal of the specification andclaims in which the invention is more forth- Reference will be made tothe accompanyi drawings in which the same reference c aracters refer tothe same parts throughout and in which:

Fig. 1 is a front elevation of a motion picturecamera embodying myinvention;

Fig. 2 is a rear elevation of the same;

Fig. 3 is. a diagram illustrative of the finder system; I

Fig. 4 is a enta sectional new on the hne 4-4 of ig. 1; t e objectivemount being omitted;

Fig. 5 is a front view of the same mechanism, the front of the camerabeing removed; Fig. 6 is a perspective view of the finder, objective andtheir correlating mechanism, the camera being indicated in dotted lines;

Fig. 7 is a diagrammatic showing of the relation of the finder to theobjective; and

a fol owing, particularly set of which the following is' The mount a reewith the exposure field of the camera,

and with no attention from the I Fi 8 is a fragmentary perspective viewshowing a modified, form of my invention- In the drawings is shown amotion picture camera comprising the usual box orcasing 1 and havingfacarrying handle 2 and operating hand e 3, the, general structure of thecamera bein of the in my copending app ication, 378,618, filed May 3,1920.

In the front 10 of the casings are openings 4 and 5 for the finder andobjective respectively, there being a spring hinged door 6 which may beheld in protective position over these by latch 7. Withinthe camera is afixed partition 8, to which is attached a support 9 carrying a tubularmember 11 having internal screw threads 12 in which the objective mount13 carrying the camera objective 45 is adjusted back and forth. 13'hasattached rigidly thereto an annular member 14, to which is pivoted at 15(Fig. 6) a link 16, pivoted 1n turn at 17 to the crank arm 18 rigid withshaft 19, which extends longitudlnally' of the camera and through theback wall 20 thereof. On its end is carried the cross member 21 which ispointed at 22 to act as an indicator in connection with the focusingscale 23, and carries lugs or finger pieces 24 by which it may beturned.

Also on the rear wall 20 of the camera are the film footage indicator25, the diaphragm scale 26, and its corresponding setting pointer 27 andthe window 28 in which is a lens 29 which will be mentioned later inconnection with the finder system.

The objective is focused by turning the cross member 21 by the lugs 24,thereby turning the annular member 14 and moving the ob'ective mount 13or a part thereof axially to focus the objective on the exposure areatition 8.

The finder system indicated di ammatically 1n Fig. 3. It comprises aront positive lens 31 and a second positive lens 32, these being sodesigned that there is formed at about the rear surface of the secondlens 32 a rea-l inverted image of the subject, which image is magnifiedand viewed through the lens 29. A mask 32 is placed immediately in frontof the lens 32 and outlines the field viewed. The mask 32' is carried bya tubular support 33 carried by frame 8, and the tgpe shown erial No.

is a simple one and is through the gate 30 in the parlens is heldagainst this mask by a tube 34 hearing against a washer 35. The tube 34extends through the partition 8 and is ex ternally screw threaded at 36.A tube 37 is screwed upon it and extends back to the rear wall of thecamera, where it is held by a mount 38 (Fig. 6) within which is the lens29. v

The front finder lens 31 is carried in a mount 39 carried in a block 40with slots 41. This block slides in a way formed by the sheet metalplate 42 with side flanges 65 and having a tubular extension 66-engagingthe collar 67 in the front opening 4. The rear of the guideway is afixed frame 43 having lugs 44 engaging the slots 41. The direction ofsliding is radial of the main camera objective 45, as indicated on thesection line 4-4 in F ig. 1. The block 40 has an extension 46 carrying apin 47 engaging in a cam slot 48 in the annular member 14. The extent ofmovement of the front lens 31 is indicated in Fig. 3, where the normalaxis of the finder system is indicated by the dot-dash line 49. The lens31 is shown with its axial line 50 raised above 49 by the distancebetween the arrowheads 51. It is capable of movement beneath it ortoward the axis of the main objective 45 by a distance indicated betweenthe arrowheads 52. This diagram indicates the movement desirable when acorrected finder system is used with an expensive camera and when veryclose agreement between the finder field .and the exposure field isdesired. Since the finder system is obviously of fixed focus, its fielddoes not for all distances agree exactly with that of the main objectiveat the exposure field. The axis 49 is, therefore, very slightly inclinedto parallelism with the main axis and intersects it at a distance, say25 feet, in front of the camera, and the finder system is focused anddesigned to give the field very exactly for this distance. For distantviews the front lens is raised slightly, as indicated, and for close-upsis lowered.

In small and inexpensive cameras for use' by amateurs such exactness isunnecessary and the finder system is built parallel with the axis of themain objective and its useful range is obtained by moving the front lens31 toward the main objective 145. In either case it is apparent that theeffective axis of the finder proper, that --is, a line passing throughthe optical center ofthe front two lenses is tilted so that itintersects the axis of the camera objective 45 at the point upon whichthe latter is focused. This is indicated diagrammatically in Fig. 7, inwhich the line 49-49 is the axis of the finder system, passing throughthe centers of all three lenses parallel to the axis 53-53 of theobjective 45, which would be its position when the camera is focused forinfinity. When the objective 45 is focused on the exposure area for anear oint, 53, the effective axis of the finder 15 the line 535556, 55and 56 being the optical centers of the lenses 31 and 32. This producesan image as before described at about the rear surface of lens 32, whichimage ismagnified and inspected through lens 29. The image is a realinverted image, as indicated by the arrows 6060; designatingrespectively the object and the image.

My invention is applicable to the ordinary reflecting type of finder,the optical of which has merely two lenses corresponding to the presentlenses 31, 32, but with a mirror between them which reverses the imageSuch a finder is shown in Fig. 8, in which 14 is the annular member onthe lens mount having the cam slot 48, in which plays the pin 47 cariredby extension 46, as hasalready been described. This extension is pivotedat 57 to the finder 58 which is pivoted as a whole at 59, and comprisesthe front lens 61, the rear lens 62 and the mirror 63, there being amask 64 in front of lens 63. In this case the effective optical axis ofthe finder system is the line 68 from the point focused on through thecenter of lens 61 to the center of lens 62 after reflection. This lineis inclined more or less to the line 69 indicating the axis of theprincipal objective, not shown, as the cam ring 14 for focusing thelatter is turned.

The operation of the described structure is believed to be obvious fromthe above description. The user sets the focusing pointer 22 on thescale 23, according to the estimated or measured distance to the subjectand looks through the finder to ascertain the field covered. The cameraor the subject is then moved until the composition as seen in the finderis to the operators liking and then he turns the operating hantile 3, asusual. Ofcourse, the focusing pointer will be changed from time to timeas the subject recedes from or approaches the The user can tell at alltimes Whether or not the subject is properly centered and whether anyundesirable features are in or out of the field.

It is apparent that numerous variations are possible, and I contemplateas within the scope of myv invention all such modifications andequivalents as fall within the appended claims.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In a photographic camera having an objective and a finder lens, meansfor simultaneously focusing the objective and. automatically moving thefinder lens in. a lateral direction only.

2. In a photographic camera having an objective and an optical findingsystem comprising a fixed rear element and a front system Inn positivelens, interconnected means for simultaneously focusing theobjective andmoving the lens in a lateral direction only.

3. In a photographic camera, an objective, at mount for said objective,a movable member adapted to act on said mount to focus the objective andcarrying a cam slot, a

finder system including a positive lens, a

mount for one of said elements slidable' transversely'of the opticalaxis of the system, and means engaging the cam and controlling themovement of the mount.

5. In a photographic camera, an objective, a mount for said objectiveadapted to be adjusted for focusing, a fixed focus finder systemincluding a positive lens, a mount for said lens movable transversely ofthe optical system and an indicating and operating means on the cameraadapted to show the distance for which the objective is focused andmeans connecting the indicating and operating means with both mounts andadapt d to operate them to focus the objective for the distanceindicated and to move the finder lens so that the axis of the findersystem will intersect the axis of the objective at the distanceindicated.

6. In a photographic camera, an objective, a mount for said objectiveadapted to be adjusted for focusing, a finding system for said camerathe effective axisof which is adjustable, the finding system being offixed focus and being particularly corrected for a position such thatits axis intersects the axis of the objective at a finite point, andbeing capable of adjustment to parallelism with the axis of theobjective and being also capable of adjustment to an inclination suchthat it intersects the axis of the objective at a point considerablynearer adjusted for focusing, a finding system for said camera theeffective axis of which is adjustable, the finding system being offixedfocus and being particularly corrected for a position such that itsaxis intersects the axis of the objective at a finite point, and beingcapable of adjustment to parallelism with the axis of the objective andbeing alsocapable' of adjustment to an in.- clination such that itintersects the axis of the objective at a point considerably nearer thecamera than the said finite point and means for simultaneously focusingthe. ob-

jective and inclining theaxis of the finding system, whereby the latterwill automatically intersect the axis of the objective at the point uponwhich the objective is focused.

8. In a photographic camera, an objective, a mount for said objectiveadapted to be adjusted for focusing, a finding system for said cameracomprising a viewing fieldand a lens adjustable transversely of thesystem, thereby changing the inclination of the axis of the system, thesystem being particularlyv corrected for a position such that its axisintersects the axis of the objective at a finite distance, but therangeof movement of the lens being such that the axis of the system maybe parallel to the axis of the objective or may intersect it at a pointconsiderably nearer than said finite point;

9. In a photographic camera, an objective, a mount for said objectiveadapted to be adjusted for focusing, a finding system for said cameracomprising a viewlng field, and a lens adjustable transversely of thesystem, thereby changing the inclination of the axis of the system, thesystem being particularly corrected for a position such that its axisintersects the axisof the objective at a finite distance, but the rangeof movement of the lens being such that the axis of the system may beparallel to the axis of the objective or may intersect it at a pointconsiderably nearer than said finite point, and means for simultaneouslyfocusing the objective and adjusting said lens whereby the axis of thefinding system will automatically intersect the axis of the objective atthe point upon which the objective is focused.

Signed at Rochester, New York, this 2nd day of Feb, 1923.

JULIEN TESSIER.

